Ambient air pollution and obesity in school-aged children and adolescents: A multicenter study in China

Environmental factors such as air pollution may contribute to the development of childhood obesity. However, current epidemiological evidence is limited and inconsistent. We investigated the associations between long-term air pollution exposure and obesity in a large population of Chinese children and adolescents. A total of 44,718 children and adolescents (50.5% boys) aged 7 to 18 years were recruited from seven provinces/municipalities in China. Body mass index (BMI), waist circumference, waist-to-height ratio (WHtR) and the prevalence of general and central obesity were measured. Satellite-based spatial-temporal models were used to estimate ambient concentrations of particulate matter with aerodynamic diameter < 1.0 μm (PM1), <2.5 μm (PM2.5), <10.0 μm (PM10) and nitrogen dioxide (NO2). We used mixed-effects linear and logistic regression models to examine the associations between air pollution exposure and body weight measures. Exposure to PM1, PM2.5, PM10 and NO2 was associated with increased BMI Z-score, waist circumference and WHtR, and higher prevalence of both general and central obesity. Generally, stronger associations were observed for particles, especially PM1 and PM2.5, than for NO2. Also, the associations of particles were generally more stable in two-pollutant models. Overall, the associations were more pronounced in boys than in girls except for general obesity. Long-term exposure to air pollution was associated with increased body weight and higher prevalence of obesity in children and adolescents, suggesting potential obesogenic effects of air pollution.